Dental device for use in the making of a crown or inlay



May 9, 1967 R. RUBIN DENTAL DEVICE FOR USE IN THE MAKING OF A CROWN OR INLAY Filed Fb. 15, 1965 INVENTOR, Robert Rubin,

ATTORNEY.

United States Patent ()fiice 3,318,001- Patented May 9, 1967 3,318,001 DENTAL DEVICE FOR USE IN THE MAKING OF A CROWN OR INLAY Robert Rubin, 19 E. 71st St., New York, N.Y. 10021 Filed Feb. 15, 1965, Ser. No. 432,673 Claims. (Cl. 32-40) The present invention relates to a dental device for use in the making of a crown or inlay for a tooth and more particularly to an improved and novel die stem construction for holding the die of an abutment tooth and to position it on the model which is a cast showing relationship of teeth to each other and of teeth to surrounding gum tissue of at least a row of teeth including such abutment tooth.

The principal object of this invention is to provide a novel and improved die stem of the character mentioned, which holds the die against relative movement and positions it on the model in precise relation; said stem being removable to facilitate making the crown or inlay, and replaceable to ascertain its correctness; there being special provision that said stem will always lit in the cast with true precision, regardless of how many times it is removed and replaced.

Another object thereof is to provide a novel and improved dental device of the type set forth, which is reasonable in cost to manufacture, easy to use and eflicient in carrying out the purposes for which it is designed.

Other objects and advantages will become apparent as this disclosure proceeds.

The present device is used in a procedure which first involves making an impression of the abutment tooth, then making a die of said tooth from said impression on a stem of non-circular cross-section, then inserting such assembly in an impression of the mouth and finally making a cast of such impression in which of course, the stem will be imbedded, and the die of the abutment tooth will be in true position in relation to adjacent teeth of said cast, or model as it is commonly called in dental nomenclature.

Heretofore, various devices of the class concerned with herein have been used, but the common faults with all of them were that too often, either the die turned on the stem, the stem turned in the model, or both such objectionable movements occurred. In some instances, the stem was removable and replaceable in the model, but they worked loose and the precision of the assembly undone.

For one practice of the present invention, I provide a non-circular cup in upright position atop the thicker end of a tapered stem having a crescent-shaped cross section. The cup is adapted to be filled with filling mate rial to serve as connecting sealer to the die to be made thereof. The crescent-shape provides the stem with two spaced acute angled wedges, and two comparatively large area curved surfaces, all of which serve to give a maximum friction hold on the model. I am utilizing the physics of the frictional hold of a wedge, in that it increases as the angle of the wedge decreases. In former devices, any wedge action offered by the stem, was by obtuse angled formations. Also shown herein, is a modified stem structure offering two acute angled wedges to attain proper frictional hold of the stem in the model.

In the accompanying drawing forming part of this specification, similar characters of reference indicate corresponding parts in all the views.

FIG. 1 is a fragmentary view of a patients teeth in the mouth, showing one abutment tooth prepared in conventional manner to receive a crown.

FIG. 2 is a perspective view shown partly in section,

of an impression of said abutment tooth made in impression material contained in a copper band.

FIG. 3 is a perspective view of a preferred emb0diment of the stemmed cup, in accordance with the teachings of this invention.

FIG. 4 is a perspective view showing the die being made from the impression illustrated in FIG. 2.

FIG. 5 is a perspective view of the die of said abutment tooth formed of impression material held in the cup portion of the device shown in FIG. 3.

FIG. 6 is a fragmentary perspective view of the impression taken of the row of teeth shown in FIG. 1 in which the laden stem of FIG. 5 is positioned so that the abutment tooths cavity properly received the die part.

FIG. 7 is an elevational view of the model or cast made of the assembly shown in FIG. 6.

FIG. 8 is an enlarged section taken at line 8--8 in FIG. 3.

FIG. 9 is like FIG. 8, but of a slightly modified section.

In the drawing, my new device indicated generally by the numeral 15, is for use in the practice of known procedure to prepare for making a crown or inlay, the principal steps of which are illustrated and will now be described with the employment of said device. The numeral 16 designates an abutment tooth prepared in conventional manner, from which an impression is made in impression material 17 contained in a band 18. Such impression is left to harden, and after it is plated with a metal film not shown, it is used to make the model or die 19 of plastic connecting self-curing material overfilling the cup 20 of my device as is shown in FIG. 4. Plastic connecting self-curing material is also placed in the metal plated band 18, and the cup 20 is placed into the band 18 and left to harden. It is then trimmed and set into the socket 21 made by the abutmenttooth 16 in the impression 22 made of the patients teeth including said tooth 16, so that the die 19 fits accurately in said socket. Now the model 23 is made of the assembly shown in FIG. 6, whereupon the device 15 is embedded as an artificial root, but the die 19 is exposed, taking the place of the tooth 16, so the crown or inlay 24 can be fashioned thereon in manner well known in the art.

The device 15, made of metal, plastic or other suitable non-resilient rigid material, is preferably an integral piece comprising the non-circular cup 20 which preferably conforms to the general size and shape of the transverse section of the tooth it is used in place of, and a tapered stem 25 which is of crescent-shaped cross section as shown in FIG. 8, or as slightly modified in FIG. 9. The cup portion is also preferably tapered in the same direction as the stem and may overhang the stem to form a stop 20 which precisely limits the extent of insertion of the device 15 into the model 23 at each replacement thereof into said model; the laden device 15 being removable from said model to facilitate fashioning a crown 24 on the die 19.

The crescent-shaped cross section of the stem 25, presents two spaced acute-angled wedges 26 and 27 along the stem; the thin edges of said wedges being along said stem. The socket in the model 23, made by the laden device 15, of course conforms and is the counterpart thereof. The comparatively greater frictional hold accomplished with acute-angled wedges 26, 27, augmented by the large surfaces 28 and 29 in frictional contact with the socket wall in the model 23, assure continuance of precision fit every time the laden device 15 is reinserted into the model. The optimum lack of looseness attained by this arrangement, avoids any possible turning move ment of the stem 25 while set in the model 23, and the cup 20 being non-circular, prevents any turning movement of the die 19 in relation to the stem 25. The smaller the angles A and A are, the better frictional hold will said wedges 26, 27 and 26', 27 have in the model 23. The cross section of the stem may also be made as in FIG. 9, which is a slightly modified crescent shape where 28' is a dihedral angle.

These devices shall be made in various sizes with suitable cup shapes to suit different teeth in a mouth. The cup may originally be made round and be distorted with pliers to suit tooth shape. The stem is relatively long to allow sufficient height so it can be held in hand, and in making the model 23, the tip end of the stem should be available to be tapped to loosen same for removal.

It is evident that for each tooth to be given a crown, one of these devices 15 is needed and several of them may appear on one model 23.

This invention is capable of numerous forms and various applications without departing from the essential features herein disclosed. It is therefore intended and desired that the embodiments shown herein shall be deemed merely illustrative and not restrictive and that the patent shall cover all patentable novelty herein set forth; reference being had to the following claims rather than to the specific showings and description herein, to indicate the scope of this invention.

I claim:

1. A dental device for holding the die of an abutment tooth which is to have a crown built thereon, adapted to be releasably held as an artificial root in a model of the mouth portion which includes said abutment tooth, a cup for holding impression material of which the die is to be fashioned, and an elongated stern extending from the exterior of the cup, away therefrom along the line of direction of the height of the cup; said cup overhanging the stem; the transverse cross section of said stem being substantially crescent-shaped.

2. In a dental device for holding the die of an abutment tooth which is to have a crown built thereon, adapted to be releasably held as an artificial root in a model of the mouth portion which includes said abutment tooth, a cup for holding impression material of which the die is to be fashioned, and an elongated stem extending from the exterior of the cup, away therefrom along the line of direction of the height of the cup; said cup overhanging the stern; said stern including at least one wedge formation along its height; the thin edge of each wedge formation being along the height of the stem and each wedge formation being acute-angled.

3. A dental device for holding the die of an abutment tooth which is to have a crown built thereon, adapted to be releasably held as an artificial root in a model of the mouth portion which includes said abutment tooth, a cup for holding impression material of which the die is to be fashioned, and an elongated stern extending from the exterior of the cup, away therefrom along the line of direction of the height of the cup; the perimetrical surface of the stem comprising two parts; one part being convex and the other dihedral whereby the transverse cross section of said stem is substantially crescent-shaped.

4. In a dental device for holding the die of an abutment tooth which is to have a crown built thereon, adapted to be releasably held as an artificial root in a model of the mouth portion which includes said abutment tooth, a non-circular cup for holding impression material of which the die is to be fashioned, and an elongated stern extending from the exterior of said cup, away therefrom along the line of direction of the height of the cup; said stem including at least one wedge formation along its height; the thin edge of each wedge formation being along the height of the stern; each wedge formation being acute angled; said stem tapering away from the cup; said cup tapering towards the stern and overhanging said stem.

5. In a dental device for holding the die of an abutment tooth which is to have a crown built thereon, adapted to be releasably held as an artificial root in a model of the mouth portion which includes said abutment tooth, a non-circular cup for holding impression material of which the die is to be fashioned, and an elongated stern extending from the exterior of the cup, away therefrom along the line of direction of the height of the cup; the transverse cross section of said stem being substantially crescent shaped; said stem tapering away from the cup; said cup tapering towards the stem and overhanging said stern.

References Cited by the Examiner UNITED STATES PATENTS 1,173,050 2/1916 Sladek 24-11 1,867,300 7/1932 Bailey 32-40 3,200,496 8/1965 Spalten 329 RICHARD A. GAUDET, Primary Examiner.

I. W. HINEY, Assistant Examiner. 

1. A DENTAL DEVICE FOR HOLDING THE DIE OF AN ABUTMENT TOOTH WHICH IS TO HAVE A CROWN BUILT THEREON, ADAPTED TO BE RELEASABLY HELD AS AN ARTIFICIAL ROOT IN A MODEL OF THE MOUTH PORTION WHICH INCLUDES SAID ABUTMENT TOOTH, A CUP FOR HOLDING IMPRESSION MATERIAL OF WHICH THE DIE IS TO BE FASHIONED, AND AN ELONGATED STEM EXTENDING FROM THE EXTERIOR OF THE CUP, AWAY THEREFROM ALONG THE LINE OF DIRECTION OF THE HEIGHT OF THE CUP; SAID CUP OVERHANGING THE STEM; THE TRANSVERSE CROSS SECTION OF SAID STEM BEING SUBSTANTIALLY CRESCENT-SHAPED. 